The excerpt word amount will be 55 words and if the amount is greater than
that, then the string ' […]' will be appended to the excerpt. If the string
is less than 55 words, then the content will be returned as is.

The 55 word limit can be modified by plugins/themes using the {@see 'excerpt_length'} filter
The ' […]' string can be modified by plugins/themes using the {@see 'excerpt_more'} filter